Playing Cards (#252500)
Of the four sets of cards included in the test materials, the Playing Cards is the easiest in measuring the visual acuity of very young children.
It functions also as regular teaching material when learning the concepts of similar/different, big/small, bigger/smaller.
Suggestions for the Play Situation
If the child has difficulties in picture perception use the Lea 3-D Puzzle (#251600) first, then compare the 3-D symbols with the pictures
of the symbols drawn by tracing around the puzzle pieces or with the pictures on the Flash Cards (#251900) before using the Playing Cards
for sorting games:
Level I: Sorting each symbol type separately
All Playing Cards with the symbol “house” are stacked one by one next to the “house” flash card. Then do the same with the “apple,” “ball,”
and “box.”
Level II. Sorting two or more symbols
• Give the child a mix of two different symbol shapes in all different sizes and have him/her sort them by matching them up with the
corresponding flash card.
• If the number of cards is too much for the child, choose three to four of the biggest sizes of both symbols. Next time you play you can
choose smaller sizes.
• Repeat Step 1 and add a third symbol and the matching flash card. Then repeat, adding the fourth symbol.
• Instead of placing the playing cards into stacks, make neat rows of cards next to the flash card(s).
• Sort the cards within the row in the order from the biggest to the smallest.
In each game situation, make sure you do not use symbols that are too small for the child to see. Later you can introduce a smaller size by
having the child look at it from a shorter distance and/or with a magnifying device.
If the child wants to play with the 3-D forms in the middle of the game, allow that, because the child may need tactile confirmation.
Visual Acuity
During the game, it becomes obvious which size of symbols is the smallest the child can respond to, thus giving you approximate visual
acuity value. To determine the child’s visual acuity you need to measure the distance at which the smallest symbol is seen. Use your hand
to measure the distance rather than a ruler so as not to disturb the play situation.
You can also measure visual acuity by asking the child to place the corresponding Lea Puzzle piece on the card that you place in front of
the child.
If you use the Lea Playing Cards as a game playing “pairs”, the child may be motivated to get quite close to the recognition threshold.
The M size, i.e. the actual size of the symbol, is printed on the back of the playing cards. The following tables give you the visual acuity
values when measured at 16, 8 or 4 inches (at 40cm, 20cm or 10cm).
If the child recognized the 1.0M symbols at a distance different from the three distances given in the table, for example at 5”, the visual
acuity is calculated using the closest distance in the following table, in this case 4 in.
www.good-lite.com
1.800.362.3860
1.888.362.2576 Fax
Letter Size
16 M
10 M
6.3 M
4.0 M
2.5 M
1.6 M
1.0 M
.63 M
40 cm (16 in) Test Distance
40 cm
20 cm
(16 in)
(8 in)
20/800
500
320
200
125
80
50
32
20/1600
1000
630
400
250
160
100
63
10 cm
(4 in)
20/3200
2000
1250
800
500
320
200
125
Similarly, if the British notation is used and the 1.6M cards were seen at 12 cm distance:
Letter Size
16 M
10 M
6.3 M
4.0 M
2.5 M
1.6 M
1.0 M
.63 M
40 cm (16 in) Test Distance
40 cm
20 cm
(16 in)
(8 in)
6/240
150
95
60
38
24
15
9
6/480
300
190
120
75
48
30
18
10 cm
(4 in)
6/950
600
380
240
150
95
60
36
If the decimal notation is used, the calculation is following: 12cm/10cm x 0.06 = 0.07
Letter Size
16 M
10 M
6.3 M
4.0 M
2.5 M
1.6 M
1.0 M
.63 M
40 cm (16 in) Test Distance
40 cm
20 cm
(16 in)
(8 in)
.025
.040
.063
.100
.160
.250
.400
.630
.0125
.020
.032
.050
.080
.120
.200
.320
10 cm
(4 in)
.006
.010
.016
.025
.040
.060
.100
.160
When using the metric system, visual acuity can also be calculated simply by dividing the distance used (in meters) by the M-value:
0.12m/1.6M = 0.07.
If the calculations are found too be difficult, writing down the M-value and the distance used is enough for follow-up. When visual acuity
values of the eyes need to be compared, as during the follow-up of training of an amblyopic eye, show the cards to the child at the same
distance. Then you can see the difference in visual acuity values as lines of visual acuity tests without any calculations.
www.good-lite.com
1.800.362.3860
1.888.362.2576 Fax